Drivetrain Fluids

[zeroping]

I had the opportunity to do all of my drivetrain fluids this past Saturday: front diff, transmission, transfer case, and rear diff (all three chambers). I ended up renting a bay with a lift at one of those "you wrench it" garages which made the job a breeze. I highly recommend Gearhead in Warwick, RI - the owner Ron is an awesome guy.

Overall an extremely simple job with most of the time being spent doing the temperature-based fill on the transmission. I had my brother in the M while in the air on the lift monitoring ISTA guiding me. I purchased the kit the reuses our special aluminum pan with a drop-in filter. There is an air guide ahead of the transmission pan that was easily removed with 3x8mm hex bolts which allowed me to easily access and torque all pan bolts and fill/drain plugs.

All adaptions were reset across the transmission, transfer case, and rear diff. Fluids were surprisingly clean at 55k miles but the cost ($848) is well worth the insurance and confidence that performing this service gives me. I can't say that the vehicle is any smoother than it was but that wasn't the point to begin with. I've worked hard to be able to obtain one of these precision machines so I maintain it above the standard to position me for years of enjoyment.

Below are the parts I used. Everything used was BMW OE except for the transmission fluid and kit which was branded ZF from FCPEuro. ISTA referenced for procedures and torque values. I can post all of that information here if it's helpful.

Front Diff:
BMW Differential Service Kit: KIT-83222413511KT

Transmission:
BMW Auto Trans Filter Kit: ZFS-1102298020
ATF8 Automatic Transmission Fluid: PEN-1058210 x2

Transfer Case:
BMW DTF1 Transfer Case Fluid: BMW-83222409710
BMW Differential Drain/Fill Plug: STC-SP00176

Rear Diff:
BMW QMV Differential Service Kit: KIT-83120445832KT

Tools acquired to make this and future services a breeze:
Euro Drain Plug Wrench (14mm Allen x 17mm Box): CTA-8762
Extraction/Filling Syringe Pump (200cc): CTA-7073

[Atomicteal_M3]

Great info! I plan on doing all of this next month. I just purchased a 2016 with 60k on the dash. I have purchased everything already to replace all fluids.

[CFALevelFore]

I’ve been told by an independent shop and a local BMW dealer here in CO that the transfer case on the F85 isn’t serviceable. It doesn’t sound like that’s the case? Mine is a 2016, not sure if it varies by year or not.

[shimmy23]

Originally Posted by CFALevelFore

I’ve been told by an independent shop and a local BMW dealer here in CO that the transfer case on the F85 isn’t serviceable. It doesn’t sound like that’s the case? Mine is a 2016, not sure if it varies by year or not.

lots of YT vids and info here on how to change the fluid. i believe FCPeuro has a video on it too. all years are serviceable

[zeroping]

Originally Posted by CFALevelFore

I’ve been told by an independent shop and a local BMW dealer here in CO that the transfer case on the F85 isn’t serviceable. It doesn’t sound like that’s the case? Mine is a 2016, not sure if it varies by year or not.

The TC is a critical component to the all-wheel drive system that is subjected to heat and friction material within a bath fluid of minimal capacity.

The transfer case on the F85 is indeed fluid serviceable. There is only a fill plug (unlike all other driveline components) so a suck/dump method is needed.

[Maverik259]

Originally Posted by CFALevelFore

I’ve been told by an independent shop and a local BMW dealer here in CO that the transfer case on the F85 isn’t serviceable. It doesn’t sound like that’s the case? Mine is a 2016, not sure if it varies by year or not.

What they meant is that the fluid is "lifetime" and not meant to be serviced per BMW's misguided attempt to save them $$. Same for the transmission. Again all BS.

As stated here there is a fill port and FCP sells a special angled metal tube designed to reach the bottom of the transfer case to help suck out the old fluid. Then fill till it just starts to flow out of the fill port. Then you have to use ISTA to reset the computer.

Luckily i was still under my BMW extended warranty when mine failed. They replaced the whole thing at the tune of $6500. Probably could have avoided this by changing the fluid around 30k miles.

I just did the differentials this weekend and it was a bitch to say the least. Hardest part was getting the fill ports of the LSD L/R and front. BMW perfectly placed rigid lines so i couldnt get my hands in there. Unfortunately didn't find the CTA 14mm tool OP mentioned until after i was done with the rear as my 14mm hex bit was too long and that tool didn't help the front at all as my Active steering lines were in the way. The FCP Euro video makes it look so easy. haha

I cautiously made sure i could remove the fill plugs before the drain plugs as i didnt want to completely screw myself.

[zeroping]

Originally Posted by Maverik259

They replaced the whole thing at the tune of $6500. Probably could have avoided this by changing the fluid around 30k miles.

I also had my TC replaced under warranty at 45k miles. When I did the change herein at 55k miles the fluid was light black. The fluid capacity in these are minimal but all that friction material and heat needs to be accounted for somewhere. BMW has a plan here...in their favor.

I will be changing my TC fluid every other oil change. Now that I've invested in the handful of tools to do the job quickly and correctly, I view this as cheap insurance that will hopefully keep me from having replace the entire unit in the future.

[Sophisticated Redneck]

Originally Posted by CFALevelFore

IÂ’ve been told by an independent shop and a local BMW dealer here in CO that the transfer case on the F85 isnÂ’t serviceable. It doesnÂ’t sound like thatÂ’s the case? Mine is a 2016, not sure if it varies by year or not.

Soooo BMW went full dick mode on the transfer case with the F85 and eliminated the drain plug. They actually started doing this on the E70 towards the end of its production and carried it over to the F85. It can still however be serviced just with the additional step of siphoning out the oil through the fill plug.

Here is a write up I did for the E70, everything applies to the F85 as it uses the same ATC 45L transfer case and not much changed underneath between the E70 & F85.

Highly recommend a good scanner like foxewell 530 or better or using ISTA to re calibrate after oil change. 185k+ miles is possible when properly maintained as I am at the mileage now in a E70 that's been tuned to 600hp and flogged daily.

https://www.xbimmers.com/forums/show....php?t=1892534



Also here is a pretty good video on it:

[NikNala]

If you have Xdelete then you can recalibrate the transfer case within the program.